Leveraging online selling through social media influencers

While prior research suggests that facial expression influences consumer behavior, it remains unclear under which conditions specific emotional expressions on social media drive sales performance and customer engagement. Drawing on the facial feedback hypothesis and the emotional congruence framework, two preregistered experimental studies (N = 995) demonstrate that the fit between facial expressions (broad vs. slight smile) and endorsement type (hedonic vs. utilitarian) influence engagement and consumers' purchase intents. Findings indicate that broad (vs. slight) smiles are more likely to enhance consumer responses when paired with hedonic endorsements driven by emotional contagion. Conversely, slight smiles are equally suited for both types of endorsements and do not foster emotional contagion. The findings offer actionable insights for maximizing consumer engagement and purchase intents within social media marketing efforts.